Survival of infants born at extremely low birth weight (ELBW, 21,000 grams) has increased. Little is known about their long term growth and functional status beyond middle childhood. The purpose of this study was to compare growth, sexual maturation and functional outcome of ELBW adolescents to normal birth weight (NBW, 32,500 grams) adolescents and to correlate findings of functional outcome with physcal growth. This study had a cross sectional design. We included 53 ELBW and 53 NBW adolescents between 12 and 18 years of age without major neuro- developmental disability (moderate cerebral palsy, mental retardation, deafness and/or blindness) matched by age, sex, race and socioeconomic status. Anthropometric measurements (z-scores), development of skeletal mass and composition assessment (dual energy x-ray absorptiometry, DEXA, and bone age), sexual maturation and functional status (using Peabody Picture Vocabulary Test [PPVT-RR] and Visual Motor Integration Developmental test [VMI], behavioral, self esteem and quality of life measures) were obtained. Subjects were 58.5% female, 41.5% males; 43.34% black and 56.6% white. Mean age (14.85 years) and Hollingshead socioeconomic score were similar for both groups. Mean birth weight was 849 gm. for ELBW and 3355 gm. for NBW. ELBW adolescents had lower mean head circumference (0.01 vs. 1.2, P<.001), mean height (-0.37 vs. 0.28, P=.0005) and weight (0.01 vs. 0.84, P+.008) z-scores. Sexual maturation was similar between groups. Using DEXA, ELBW adolescents had lower total lean mass, total muscle mass, total fat and total bone mineral content. However, percent of body fat and ratios of total fat/lean mass and total bone content. However, percent of body fat and ratios of total fat/lean mass and total bone content/lean mass were not different. Bone mineral density was not significantly different between the groups. Bone age, measured in standard deviation units, was higher on the ELBW groups (0.86 vs. 0.42, P=.04). the PPVT-R (89.5 vs 102.7, P=<.0001) and VMI (84.6 vs 90.9, P=.006) scores were lower for ELBW. Height correlated with PPVT-R and VMI scores in the ELBW group. In summary, ELBW adolescents who survived without a major neuro- developmental disability have lower anthropometric measurements, however, similar body composition and sexual maturation than NBW adolescents. On the vocabulary tests and visual motor integration tests we used, ELBW adolescents scored lower than NBW adolescents and these scores were associated with height measurements in our sample of ELBW adolescents.